Scríobhfaidh mé chugat go gairid.
as Gaeilge
It's already written in Irish.
In the Irish language: Ó Duibhir
Rinne mé.
cúig
SibealÉilís
fírinne
Seán
Write to you soon as a phrase is not one specific part of speech. Write is a verb. To is a preposition. You is a pronoun (object of the preposition.) Soon is an adverb.
Mo Bhanphrionsa Gaelach / Mo Bhanphrionsa Éireannach
The Irish word for 'cake' is ciste [kishtih] or cáca [kawka].
with a pen and paper